A review of the phytochemistry, botany, pharmacology and toxicology of Arctotis arctotoides

Background: Arctotis arctotoides (Asteraceae) is commonly used by the rural people of Eastern Cape for the treatment of epilepsy, indigestion, catarrh and stomach ache. The leaf paste or juice is applied topically in the treatment of wounds and skin disorders. Unfortunately, no previous reviews are available for this important medicinal plant. Hence, the aim of this review is to provide a comprehensive overview of the botany, phytochemistry, pharmacology and toxicology of Arctotis arctotoides.Methodology: This review was carried out using a comprehensive and systematic literature search on the following databases: Google Scholar, PubMed, Science Direct and Scopus. Searches were undertaken using the key word “Arctotis arctotoides” and the six synonyms of Arctotis arctotoides identified in the Plant List.Results: In the first phyto-chemical study of Arctotis arctotoides, the authors reported that sesquiterpenoids presence was predominant in the root oil whereas, the essential oils of the leaves, flowers and stems had both monoterpenoids and sesquiterpenoids. The literature survey revealed that Arctotis arctotoides has been investigated in four pharmacological areas, including anti-bacterial, anti-fungal, anti-cancer and anti-oxidant activities. Three toxicity screens for the crude extracts of A. arctotoides on cell lines, rats and brine shrimp were identified in the literature.Conclusion: Detailed studies on the bioactivity of the crude extracts and the isolated phyto-chemicals have provided partial evidence as regards the traditional use of A. arctotoides in the treatment of wounds in Eastern Cape of South Africa. However, in order to fully exploit the medicinal potential of A. arctotoides, the expansion of existing traditional knowledge into neighboring communities where the plant is not currently in use for the stated indications will support a greater use of the plant in primary healthcare.Key words: Arctotis arctotoides, botany, phyto-chemistry, pharmacology and toxicologyList of abbreviations: ABTS: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid; BHT: Butylated hydroxytoluene; DPPH: 1,1-diphenyl-2-picrylhydrazyl ; FRAP: Ferric reducing ability of plasma; MIC: Minimum inhibitory concentration; MTT: 3-(4,5-dimethythiazol-. 2-yl)-2,5-diphenyltetrazolium bromide; RPMI 1640 medium: Roswell Park Memorial Institute medium; SEM: Scanning electron microscope; TLC: Thin layerchromatography

Cytotoxicity Of Three South African Medicinal Plants Using The Chang Liver Cell Line

Background: Arctotis arctotoides, Gasteria bicolor and Pittosporum viridiflorum are commonly used in the Eastern Cape, South Africa by traditional healers for the treatment of opportunistic fungal infections in HIV/AIDS patients. Unfortunately, there is a dearth of published data regarding the toxicity of the selected plants, despite the fact that experimental screening of toxicity is crucial to guarantee the safety of the users.Materials and Methods: Therefore, it was decided to evaluate the cytotoxicity of the hexane and acetone extracts of the medicinal plants against the Chang Liver cell line using the in vitro MTT assay. Different concentrations of the extracts were added into 24-hour cultured cells and incubated for 72 hours under specific condition (37 °C, 5% CO2). Cell survival was evaluated using the 3-(4, 5-dimethylthiazol-2-yl)-2,  5-diphenyltetrazolium bromide (MTT) assay.Results: Depending on the dosage and duration of treatment, the cytotoxic effects of Gasteria bicolor and Pittosporum viridiflorum were considered relatively weak (but not entirely absent) and less of a toxicity risk. Arctotis arctotoides extracts were the most toxic both in terms of IC50 values as well as the steeper slope of the dose response curve. The IC50 values for the acetone and hexane extracts of this plant were 17.4 and 12.4 μg/ml respectively.Conclusion: These relatively low values raise concern for potential hepatotoxic effects and deserve further investigation or at least a warning to potential users.Keywords: Cytotoxicity; medicinal plants; opportunistic fungal infections; Chang liver cell lin

Foliar micro-morphology of Gasteria bicolour haw. (Asphodelaceae) from South Africa

Background: The succulent genus, Gasteria, which comprises 16 species, is endemic to South Africa and has its main centre of distribution in theSavanna Region of the Eastern Cape. Whereas G. bicolor has been investigated phyto-chemically and pharmacologically, not much data  concerning the anatomical and micro-morphological features can be found in literature.Materials and Methods: This study was undertaken, using light and scanning electron microscopy to obtain information on the micro-morphological features of this important medicinal plant to facilitate itsidentification and authentication. The elemental composition of the leaf was determined by energy dispersive X-ray spectroscopy (EDXS).Results: The epidermal cells are either hexagonal or pentagonal in form, and are compactly arranged with undulate anti-clinal cell walls. Theepidermal cell width was approximately 50 µm. Stomata apertures are elliptical and the upper epidermis of the leaf has paracytic stomata which are slightly raised above the epidermal surface with 4 to 5 subsidiary cells surrounding each stoma. Based on the EDXS microanalysis, the mineralcrystals present at the level of the mesophyll of G. bicolor were probably mixtures of calcium oxalate, calcium sulphate and silica.Conclusion: The co-occurrence of aluminum suggests the potential role of the crystals in detoxification of aluminum and heavy metals, as reportedpreviously.Key words: Foliar micro-morphology, Gasteria bicolor, light microscopy, scanning electron microscop

Phytochemical studies and antioxidant activity of two South African medicinal plants traditionally used for the management of opportunistic fungal infections in HIV/AIDS patients

<p>Abstract</p> <p>Background</p> <p>It has been observed that perturbations in the antioxidant defense systems, and consequently redox imbalance, are present in many tissues of HIV-infected patients. Hence, the exogenous supply of antioxidants, as natural compounds that scavenge free radicals, might represent an important additional strategy for the treatment of HIV infection. The aim of this study was therefore to analyse the phytochemical constituents and antioxidant potential of <it>Gasteria bicolor </it>Haw and <it>Pittosporum viridiflorum </it>Sims., two South African plants traditionally used for the management of opportunistic fungal infections (OFIs) in AIDS patients.</p> <p>Methods</p> <p>The <it>in vitro </it>antioxidant properties of the two plants were screened through DPPH (1,1-diphenyl-2-picrylhydrazyl), NO (nitric oxide), H₂O₂(hydrogen peroxide) radical scavenging effects and reducing power assays. Phytochemical studies were done by spectrophotometric techniques.</p> <p>Results</p> <p>There were no significant differences in the flavonoid and proanthocyanidins contents between the leaves and bark extracts of <it>Gasteria bicolor </it>and <it>Pittosporum viridiflorum </it>respectively, while the total phenolic content of the bark extract of <it>P. viridiflorum </it>was significantly higher than that of <it>G. bicolor </it>leaf. The acetone extracts of both plants indicated strong antioxidant activities.</p> <p>Conclusion</p> <p>The results from this study indicate that the leaves and stem extracts of <it>Gasteria bicolor </it>and <it>Pittosporum viridiflorum </it>respectively possess antioxidant properties and could serve as free radical inhibitors, acting possibly as primary antioxidants. Since reactive oxygen species are thought to be associated with the pathogenesis of AIDS, and HIV-infected individuals often have impaired antioxidant defenses, the inhibitory effect of the extracts on free radicals may partially justify the traditional use of these plants in the management of OFIs in HIV patients in South Africa.</p